NSString URL decode?

ios, nsstring, percent-encoding, urldecode

Solution

Use `CFSTR("")` instead of `NULL` for the second to last argument. From the CFURL reference:

charactersToLeaveEscaped

Characters whose percent escape sequences, such as %20 for a space character, you want to leave intact. Pass NULL to specify that no percent escapes be replaced, or the empty string (CFSTR("")) to specify that all be replaced.

    NSString *encoded = @"fields=ID%2CdeviceToken";
    NSString *decoded = (__bridge_transfer NSString *)CFURLCreateStringByReplacingPercentEscapesUsingEncoding(NULL, (CFStringRef)encoded, CFSTR(""), kCFStringEncodingUTF8);
    NSLog(@"decodedString %@", decoded);

Prints:

2013-03-26 21:48:52.559 URLDecoding[28794:303] decodedString fields=ID‭,‬deviceToken

Problem

I have tried a lot of approaches out there, but this tiny little string just cannot be URL decoded. ``` NSString *decoded; NSString *encoded = @"fields=ID%2CdeviceToken"; decoded = (__bridge NSString*)CFURLCreateStringByReplacingPercentEscapesUsingEncoding(NULL, (CFStringRef)encoded, NULL, NSUTF8StringEncoding); NSLog(@"decodedString %@", decoded); ``` The code above just logs the same (!) string after replacing percent escapes. Is there a reliable solution out there? I think some kind of RegEx solution based on some documentation could work. Any suggestion?

Original source